Important Service Announcement: Based on user feedback we are not shutting down the TaxAlmanac.org website however the site is now an archived version as of June 2014. While all of the existing discussion threads and commentary will be preserved you will no longer be able to edit content, post to forums or create additional logins.

What should I do if I made a mistake on my federal return that I have already filed?

It depends on the type of mistake that was made. Many mathematical errors are caught in the processing of the tax return itself. If you did not attach a required schedule the service will contact you and ask for the missing information.

If you did not report all your income or did not claim a credit, you are entitled to file an amended or corrected return using Form 1040X, Amended U.S. Individual Income Tax Return. Include copies of any schedules that have been changed or any Forms W-2 you did not include. The Form 1040X should be submitted after you receive your refund or by the due date of the return, whichever, is earlier. Generally, to claim a refund, the Form 1040X must be received within three years after the date you filed your original return or within two years after the date you paid the tax, whichever is later.

I received a refund that is more than I should have received because I've discovered I made a mistake on my return. I have not yet cashed this check. What should I do now?

Many mistakes are corrected in processing and a letter of explanation is mailed at the time the refund is issued. If the mistake was not corrected in processing, you need to file an amended or corrected return using Form 1040X (PDF) , Amended U.S. Individual Income Tax Return, as soon as possible. Include copies of any schedules that have been changed or any Forms W-2 you did not include. If you return the refund check with a letter of explanation, a refund in the correct amount will be issued when the amended return processes.

Form 1040X (PDF), Amended U.S. Individual Income Tax Return, is designed with three columns. Column A is used to show the figures from the original return. "However, if you previously amended that return or it was changed by the IRS, enter the adjusted amounts." Column C is used to show the correct figures. The difference between the figures in Columns A and C is shown in Column B. On the back of the form you need to explain the specific changes being made on the return and the reason for each change. If the changes involve another schedule or form, attach it to Form 1040X. Be sure to enter the year of the return you are amending at the top of the form as required.

References:

Form 1040X (PDF), Amended U.S. Individual Income Tax Return and Instructions

No, an amended return must be filed on a paper Form 1040X (PDF), Amended U.S. Individual Income Tax Return, and mailed to your servicing center for processing. You may submit the form once your original return has processed.

Once accepted, you must allow the e-file return to process before making any changes. You cannot correct a mistake on a federal return which was filed electronically. You need to file an amended or corrected return using Form 1040X (PDF), Amended U.S. Individual Income Tax Return, as soon as possible. Include copies of any schedules that have been changed or any Forms W-2 you did not include. The 1040X is a paper form.

You will need to contact our assistance line at (800) 829-1040 to receive information on the processing of your amended return. Amended/corrected returns are processed as quickly as possible. However, it could take 8 to 12 weeks to process an amended return.

If I call the automated tax line to check the status of a refund on an amended return, do I enter the total amount of my original refund, or only the amended amount?

You cannot check the status of a refund for an amended return on the automated tax line. Amended/corrected returns are processed as quickly as possible. However, it may take 8 to 12 weeks or longer to process the return. If 8 weeks have elapsed and you have not received your refund, call (800) 829-1040.